U.S. patent number 5,514,260 [Application Number 08/391,601] was granted by the patent office on 1996-05-07 for apparatus for simultaneous plating.
This patent grant is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to O. Gweon Seo.
United States Patent |
5,514,260 |
Seo |
May 7, 1996 |
Apparatus for simultaneous plating
Abstract
The present invention relates to an apparatus for simultaneous
plating with which arc ion plating and hollow cathode discharge
(HCD) ion plating can be concurrently carried out in one chamber,
and sputtering plating can also be performed in the other chamber
while the former two types of platings are being performed. Since
only one type of plating can be performed in one chamber with a
conventional apparatus, there have been problems such as excessive
installation cost and inferior plating quality. According to the
present invention, simultaneous arc ion plating and HCD ion plating
in one chamber and sputtering plating in the other one is possible,
which may lower the installation cost and improve the plating
quality.
Inventors: |
Seo; O. Gweon (Seoul,
KR) |
Assignee: |
Samsung Electronics Co., Ltd.
(Suwon, KR)
|
Family
ID: |
26012503 |
Appl.
No.: |
08/391,601 |
Filed: |
February 21, 1995 |
Current U.S.
Class: |
204/298.26;
204/298.05; 204/298.25; 204/298.41 |
Current CPC
Class: |
C23C
14/32 (20130101); C23C 14/34 (20130101); C23C
14/56 (20130101) |
Current International
Class: |
C23C
14/56 (20060101); C23C 14/34 (20060101); C23C
14/32 (20060101); C23C 014/34 (); C23C
014/32 () |
Field of
Search: |
;204/298.05,298.25,298.26,298.41 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Weisstuch; Aaron
Attorney, Agent or Firm: Cushman Darby & Cushman
Claims
What is claimed is:
1. An apparatus for simultaneous plating comprising;
a first chamber in which arc ion plating and HCD ion plating may be
concurrently or selectively performed;
a second chamber in which a sputtering plating may be
performed;
a vacuum pump which is connected to said first and second chambers;
and
two throttle valves each of which is connected to one of said two
chambers.
2. An apparatus for simultaneous plating as claimed in claim 1,
wherein an arc source and an HCD source are respectively located in
upper and lower parts of said first chamber, the plating material
for HCD plating is placed in a container mounted on the bottom of
the first chamber, and the plating material for arc ion plating is
mounted directly on the arc ignitor without using a container.
Description
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for simultaneous
plating, and more particularly to an apparatus with which arc ion
plating, HCD(hollow cathode discharge) ion plating, and sputtering
plating can be performed simultaneously. In general, vacuum
deposition is divided into physical vapor deposition (PVD) and
chemical vapor deposition (CVD). The physical vapor deposition may
also be divided into evaporation, ion plating, and sputtering.
In more detail, the ion plating may be divided further into arc ion
plating, hollow cathode discharge (HCD) ion plating, and
multi-cathode ion plating. These different kinds of ion plating can
be used for various purposes, and the merits and demerits of the
above ion platings are also different from each other. According to
the conventional vacuum plating apparatuses, only one type of
plating can be performed in one chamber. In other words, it is
usual that arc ion plating and HCD ion plating are performed in
different chambers. Consequently, a seperate apparatus for each
different kind of plating must be provided making the installation
cost of such apparatus relatively high. Further, it is difficult to
improve the plating quality of such apparatus because of the
problems relative to the plating method itself. For example, in the
case of arc ion plating and HCD plating, the coated surface is not
smooth and the bonding strength of the coated film is not
satisfactory.
SUMMARY OF THE INVENTION
The object of the present invention is to provide an apparatus with
which simultaneous performing of different types of platings are
possible. Another object of the present invention is to provide an
apparatus with which arc ion plating and hollow cathode discharge
(HCD) ion plating can be performed simultaneously in one of two
chambers therein.
Still another object of the present invention is to provide an
apparatus for simultaneous plating in the second chamber of which
sputtering plating is performed simultaneously while other types of
platings are being performed in the first chamber.
Further object of the present invention is to provide an ion
plating apparatus which produces a coated film of excellent
adhesive quality by installing an ion beam source.
To accomplish the above and other objects of the present invention,
the apparatus according to the present invention is provided with
two chambers, and a vacuum pump and two throttle valves for common
use of the pump by the two chambers, wherein are provided an arc
source and an HCD source in a chamber for performing arc ion
plating and HCD ion plating at the same time, and a sputtering
plating device in another chamber in which sputtering may be
performed simultaneously with the plating operations in the first
chamber.
The vacuum pump is shared by the first chamber, in which both of
arc ion plating and hollow cathode discharge (HCD) ion plating are
concurrently performed, and the second chamber in which sputtering
plating is performed. Since the pressures required in the first
chamber and the second chamber may be different, there are provided
two throttle valves in a series of pipes connecting the two
chambers.
In general, for vacuum evaporation, an object for plating is placed
at an appropriate position in a plating chamber. A plating material
is placed under the object for plating, and a heating device for
evaporating the plating material is arranged under it. With the
heating device, the plating material begins melting and then is
evaporated. When the plating material is evaporated, its molecules
escape from the material by molecular movement and approach the
object for plating, resulting in an adhesive coat on it.
However, in the present invention, the plating material is placed
on an arc ignitor for arc ion plating. The above object and the arc
ignitor are placed in the upper part of the first chamber to allow
for concurrent HCD ion plating in the same chamber. Thus, a device
for HCD ion plating is mounted in the lower part of the
chamber.
The arc ignitor produces an arc on the plating material at the
first stage, and the arc is then continuously produced from the
material itself. This means that the plating material itself acts
as an arc source. With the arc, the plating material is
instantaneously melted and ionized. The ionized particles of the
plating material move into the inner space of the chamber, bombard
the object for plating with a great impact and form a coated film
on it.
The chamber is filled with inert gas and maintained under a
pressure near a vacuum state of 10.sup.-2 .about.10.sup.-3 torr. At
this time, the temperature of the arc is about 4.times.10.sup.3
.about.4.times.10.sup.4 .degree.K.
Also, a voltage of about 800.about.1,000 V is applied to the object
for plating. The initial arc produced by the arc ignitor moves on
the surface of the plating material at a speed of about 100 m/sec
resulting in melting and ionizing of the plating material. In arc
ion plating, the plating material is placed on the arc ignitor and
therefore, a holder for the material is not necessary.
In HCD ion plating, a container for the plating material is mounted
on the bottom of the first chamber and the object for plating is
arranged in the lower part of the chamber. Consequently, arc ion
plating and HCD ion plating can be concurrently performed.
The HCD source is mounted on the lower part of wall of the chamber
so that thermoelectrons ejected from the source can collide with
the object for plating.
The HCD source is made of a hollow tantalum rod inserted into a
pipe with one open end. The space between the tantalum rod and the
pipe is also filled with the same inert gas as that in the chamber,
which is in a plasma state. This plasma state is separated and
different from the other plasma state formed in the chamber. When a
voltage is applied to the cathodic tantalum rod, the tantalum rod
reacts with the inert gas in the plasma state. As Argon
ions(Ar.sup.+) in the plasma state collide with the tantalum rod,
the temperature of the rod becomes over 2,000.degree. C. and the
rod radiates thermoelectrons. The flow of those thermoelectrons is
then deflected toward the plating material in the container and
consequently the thermoelectrons collide with the plating material
and melt it.
When the plating material is melted, atoms evaporate and escape
from the plating material. To ensure that the atoms are ionized and
adhere to the object for plating, the chamber should be maintained
under the plasma state when the plating material is melted. The
electrons in the plasma state collide with atoms from the plating
material and the atoms are changed into ionized particles. The
plating material thus becomes ionized, adheres to the above object
and forms a coated film.
Here, the word plasma means ionized gas. There exist neutral gas,
ions and electrons in the plasma, and the plasma is electrically
neutral because the numbers of ions and electrons are nearly
equal.
One plasma state is formed in the space between the tantalum rod
and the pipe with inert gas, while the other one is formed under
the object for plating with atoms from the plating material.
In the present invention, sputtering plating can be performed in
the second chamber. The chamber is filled with inert gas and the
pressure is maintained at about 10.sup.-4 torr. The pressure of the
chamber for sputtering plating may also be maintained lower than
that of the first chamber.
In the second chamber, the inert gas is in a plasma state as in the
first chamber. A high voltage is applied to the plating material
and atoms are separated for the material by a magnetron source. The
separated atoms collide with the inert gas ions in the plasma state
to thereby form another plasma region.
Next, a voltage is applied to the object for plating acting as a
cathode, and the ions in the plasma state from the plating material
adhere to the above object to form a coated film on it.
According to the present invention, arc ion plating and HCD ion
plating thus can be concurrently carried out in one chamber, and
sputtering plating can be also performed in the other one at the
same time. To accomplish the above, only one pump is used,
replacing the vacuum pumps of each chamber in the conventional
apparatus, and two throttle valves are provided near the outlets of
the chambers for keeping the chambers under the different pressure
conditions as required.
The throttle valve plays an important role in maintaining the
pressure of any chamber to a near vacuum state before the plating
operation starts.
When the fluid is in a viscous flow state, the pressure of which is
over 10.sup.-3 torr, the length of the pipe connected to the vacuum
pump is an important variable to the quantity of exhaust gas. On
the other hand, when the pressure of the chamber is below 10.sup.-3
torr, near to a high vacuum state as the result of continuous
exhaust, i.e. in a molecular flow state, the diameter of the pipe
is a more important variable than the length of the pipe. The
throttle valves are thus provided to control the flow of the fluids
in the chambers.
Further, according to the present invention, the molecular movement
energy of the plating material ions is increased by the ion beam
source. The bonding strength of the coated film is consequently
improved.
BRIEF DESCRIPTION OF THE DRAWINGS
The above objects and the additional advantages of the present
invention will become more apparent by describing in detail a
preferred embodiment thereof with reference to the accompanying
drawings in which;
FIG. 1(a) is a sectional view showing an evaporation plating
process.
FIG. 1(b) is a sectional view showing an arc ion plating
process.
FIG. 1(c) is a sectional view showing a hollow cathode discharge
(HCD)ion plating process.
FIG. 1(d) is a sectional view showing a sputtering plating
process.
FIG. 2 is a sectional view showing the apparatus for simultaneous
plating according to the present invention.
FIG. 3 is a block diagram illustrating the plating process by the
apparatus for simultaneous plating according to the present
invention,
FIG. 4(a) is a perspective view of the apparatus for simultaneous
plating according to the present invention,
FIG. 4(b) is a plan view of the apparatus for simultaneous plating
according to the present invention, and
FIG. 4(c) is a front view of the apparatus for simultaneous plating
according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with
reference to the drawings.
FIG.1(a) and FIG. 1(b) are sectional views showing vacuum
evaporation and arc ion plating processes, respectively.
The object for Plating M is placed at an appropriate position in
the plating chamber A or B. In the chamber A, a plating material T
is located on a heating device H for vacuum evaporation. Also, in,
the chamber B, another plating material T is mounted on an arc
ignitor I for arc ion plating. The plating material T is melted and
evaporated by the heating device H. Evaporated particles of the
plating material T move into the inner space of the chamber A,
adhere to the object M and form a coated film on the surface of the
object.
The arc ignitor I in the chamber B produces a continuous arc on the
plating material T.
With the arc, the plating material T is instantaneously melted and
ionized. The ionized particles of the plating material move into
the space in the chamber B, bombard the object M with a great
impact and form a coated film on it.
At this time, the chamber B is filled with inert gas such as Argon
gas and maintained in a vacuum state of 10.sup.-2 .about.10.sup.-3
torr and at a high temperature of about 450.degree. C. A voltage of
about 800.about.1,000 V is then applied to the object for plating
M. The initial arc produced by the arc ignitor I moves on the
surface of the plating material T at a speed of about 100 m/sec,
causing the plating material T to be melt and ionized. Those ions
adhere to and then form a coated film on the surface of the above
object M.
FIG. 1(c) is a sectional view showing a hollow cathode discharge
(HCD) ion plating process.
A container 3 for the plating material T is placed on the bottom of
the chamber C and an object for plating M is arranged at an
appropriate position in the upper part of the chamber. An HCD
source H is installed on the lower end portion of the wall of the
chamber C. The flow of thermoelectrons escaping from the HCD source
H is deflected by a an applied magnetic field, resulting in
collisions with the plating material T.
The plating material T is instantaneously melted by the
thermoelectrons and changed to an atomic state. The atoms then
escape from the plating material T and begin movement in the
chamber C and ultimately towards the object M. These atoms are
ionized by colliding with the thermoelectrons in the plasma state
and form another plasma region under the object M, where the ions
of the plating material T become anions. A voltage is applied to
the object M as a cathode, and the ions of the plating material T
in the plasma state then move and adhere to the above object M and
form a coated film thereon.
FIG. 1(d) is a sectional view showing a sputtering plating
process.
An object for plating M is placed in the upper part of the chamber
D and a plating material T is located in the lower part therein.
The chamber D is also filled with inert gas such as Ar gas and
maintained in a plasma state. The pressure of the chamber D is
maintained at about 10.sup.-4 torr, and the temperature is not so
high as that of the above chambers A, B or C. The plating material
T is also changed into an atomic state by the voltage applied to
it.
The sputtered atoms from the plating material are changed to a
plasma state in the space near the object for plating M, and the
ions of the material T then adhere to the object M.
FIG. 2 is a sectional view showing the apparatus for simultaneous
plating according to the present invention.
An arc source 1 and an HCD source 2 are respectively located in the
upper and lower part of wall of the first chamber E. An object
M.sub.1 for arc ion plating is placed near the arc source 1, and an
object M.sub.2 for HCD ion plating is mounted thereunder.
Containers 3 for plating material T are located on the bottom of
the chamber E. As mentioned above a holder, for plating material is
not necessary for arc ion plating.
The apparatus according to the present invention is thus designed
so that arc ion plating may be performed in the upper part of the
first chamber E and HCD ion plating may be concurrently performed
in the lower part of the same chamber E.
The first chamber E and the second chamber F are provided with one
vacuum pump 7 through pipes connected to two throttle valves
therein. According to the present invention, the molecular flow in
the pipe can be varied by controlling the two throttle valves 4
located adjacent to the corresponding outlets of the chambers, so
as to maintain the two chambers under different and appropriate
pressures.
There are provided two arc sources 1, two HCD sources 2 and two
plating material containers 3 in the embodiment of the present
invention. However, the number of arc sources 1, HCD sources 2, and
containers 3 arc not limited to those numbers as above in the
present invention.
FIG. 3 is a block diagram illustrating the plating process of the
apparatus for simultaneous plating according to the present
invention.
After cleaning the object for plating to wash off impurities, the
objects for plating are placed in the first chamber and the second
chamber. The unnecessary gas remaining in the two chambers is
exhausted, resulting in removal of impurities, and the pressures of
the chambers arc maintained at about 5.times.10.sup.-6 torr.
Oxides or other harmful materials on the above object arc then
removed by heating the object to a temperature of about 500.degree.
C. During this step, the exhaust is also carried out for the
removal of the heated oxide particles anti other materials.
Next, plasma cleaning is performed by filling the chambers with an
inert gas such as Ar gas. Plating is then performed by operation of
the arc source, HCD source, or magnetron source. The thickness of
plating may be desirably between about 3.about.5 .mu.m. It is
desirable to form a base layer on the object, for plating, so as to
ensure strong adhesion of the plating material to the object. For
example, in the case of titanium nitride plating, a preliminary
plating using titanium as the plating material may be carried out
for better adhesion.
With the apparatus according to the present invention, since arc
ion plating and HCD plating are concurrently carried out in the
same chamber and the base layer is firs fly formed, the coated
surface is smooth and the bonding strength is excellent. After the
plating process is completed, the coated object is finally
cooled.
FIG. 4(a) is a perspective view showing the apparatus for
simultaneous plating according to the present invention.
The apparatus according to the present invention has two view ports
for each of the chambers. The entire of plating thus can be
observed through those ports.
FIG. 4(b) is a plan, view of FIG. 4(a) showing the apparatus for
simultaneous plating according to the present invention. And, FIG.
4(c) is a front view of FIG. 4(a) showing the apparatus for
simultaneous plating according to the present invention.
Two throttle valves mounted near the outlets of the first and the
second chambers are seen in the drawing.
According to the apparatus for simultaneous plating of the present
invention, arc ion plating and hollow cathode discharge (HCD) ion
plating may be concurrently performed in the first chamber, and
sputtering plating can also be simultaneously carried out in the
second chamber, while the former two types of platings are being
performed in the first chamber. As a result, plating of excellent
quality can be performed and the above mentioned problems of arc
ion plating and HCD ion plating are thus solved.
Additionally, multi-layer plating can be easily performed with high
productivity and a decrease in the cost of coated film
formation.
Although the present invention has been described with respect to a
preferred embodiment with reference to the accompanying drawings,
the scope of the present invention shall not be limited by the
specific embodiment herein, and variations and modifications may be
readily made within the scope of the teachings of the present
invention by one skilled in the art.
* * * * *